Johann Peter Süßmilch or Süssmilch (September 3, 1707 in Zehlendorf - March 22, 1767 in Berlin) was a German priest, statistician and demographer.
He studied medicine and theology at Jena and Halle and in 1741 was an army chaplain in the First Silesian War. On Sunday, 13 August 1741, the former field preacher gave his inaugural sermon as pastor of the community Etzin.[1] Since 1742 he served as Provost in the St. Petri parish in Berlin-Cölln. He became a member of the Prussian Academy of Sciences in 1745. He discussed with Gotthold Ephraim Lessing and Immanuel Kant.
Süßmilch's most important publication on The Divine order in the circumstances of the human sex, birth, death and reproduction which he wrote in 1741 is regarded as a seminal and pioneering work in demography and the history of population statistics. Süssmilch discovered that, on the long run, there is a constant sex ratio of 1,000 female births to 1,068 male births, which he saw as a proof of the Divine working in this World. Due to this work he can be regarded as one of the founding fathers of demography in Germany. However, he refers in his work to Kaspar Neumann's work, who calculated a monthly statistics of deaths by age and death cause already between 1687 and 1691 in Breslau (present-day Wrocław). Süssmilch also worked on life tables.